Hydraulic pump or motor



Patented Dec. 28, 1937 UNITED STATES PATENT OFFICE 2,103,313 HYDRAULIC PUMF on MOTOR Elek K. Benedek, Bucyrus, Ohio Application October 21, 1935, Serial No. 45,903

Claims.

' operating pins in free but accurate rolling cooperation with the reactance rotor and in free rotatable relationship to the piston crossheads.

Another object is to provide a; reactance rotor of simplified structure having reactance grooves for cooperation with the piston cross pins and so cooperated therewith that wear is uniform throughout the entire circumference of the reactance surfaces of the grooves.

A more specific object is to provide a reactance:

having a maximum depth commensurate with a comparatively small radial overall dimension of the pump or motor.

Another and more specific object is to provide anti-friction bearing means respectively for supporting the barrel, for constraining the pintle and barrel to proper coaxial relation, and for mounting the rotary reactance, which bearing means are so related that the wear on all will be substantially equal and uniform, thus greatly increasing the useful life of the structure and reducing cost of servicing and replacements of parts.

Another specific object is to damp vibrations and shocks by means of a flexible connection between the barrel and the impeller shaft.-

Another specific object is to provide a radially flanged barrel pump or motor of this character in which more of the metal of the flange is utilized for a fly wheel effect.

Other objects and advantages of the invention will become apparent from the following specification wherein reference is made to the drawings in which Fig. 1 is a longitudinal sectional view of a pump or motor embodying the principles of the present invention and is taken on a plane indicated by the line 1-! of Fig. 2;

' Fig. 2 is a cross sectional view taken on the plane indicated by the line 22 of Fig. 1;

Fig. 3 is a fragmentary sectional view of the pintle and a portion of the barrel and is taken 7 on a. plane indicated by the line 3-3 in Fig. 1;

Fig. 4 is a right end elevation of the barrel, part thereof being shown in section for clearness in illustration;

Fig. 5 is a fragmentary end elevation of one of g the reactance rings of the present invention;

Fig. 6 is a sectional view taken on a plane indicated by the line 6-6 of Fig. 5; i

Fig. 7 is a fragmentary sectional view of the.

impeller shaft and mounting land is taken. on a plane indicated by the line l,-"- of Fig. 1; Figs. 8 and!) arerespectively a side andend elevation of a piston and associat the present inventioni Fig. 10 is an elevation of a cross pin; Fig. 11'is an elevation of a, capillary I roller; I Fig. 12 is an elevation of a retaining washer for retaining the capillary needles in the piston crosshead bore:

e cross. had of Fig. 13 isa sectional view taken on a ane'mdicated by the line l3-l3 of Fig. 12 and Figs. 14 and 15 are an elevation and an end view respectively of one of the rollers for maintaining the pintle and barrel in proper coaxial relation.

Referring to the drawings. the operating structure is mounted in a rig'idweight supporting housing l which comprises an annular wall portion la terminating at one end in a radiali'ntegral flange wall lb which, in turn, terminates inwardly in an integral hub portion 10, the housing being closed at the opposite end by a suitable bellshaped end cover 2 secured to the annular wall portion la by bolts, as illustrated.

Mounted within the hub portion lc of the housing is a valve pintle 3 having an enlarged rigid shank portion 3a'fixedly secured in the hub lc. The pintle 3 extends into the interior of the housing and has formed on its outer surface adjacent the shank a bearing race 3b and at its opposite, or free end, a race 30. The race portion 3b is of less diameter than the shank 3a of the pintle defining a radial guide shoulder 3e for a purpose later to be described.

Intermediate the races 3b and 3c, the pintle has a valve portion 3d tapered from adjacent the race 31) toward and to the race 30. In the pintle valve portion are reversible'valve ports 4 and 5 respectively, the ports being diametrically opposite from each otherrand separated by suitable diametrically opposite valve bridges. The port 4 communicates through longitudinal ducts 6 in the pintle with a main port 8 -in the shank portion 3a. The port 5 communicates through longitudinal ducts l in the pintle with a main port 9, located in the shank portion 3a and diametrically opposite from the port 8, thus completing the internal fluid circuit. The ports Band 9, in turn, are in communication with the external fluid circuit through suitable bores (not shown) formed in the hub portion lc of the housing.

Mounted within the housing in coaxial relation with the pintle 3 is a cylinder barrel l0 having a valve bore Illa tapered complementary to the valve portion 3d of the pintle, the barrel fitting the pintle with positive radial clearance for permitting hydrostatic balance of the pintle as set forth in my co-pending application, Ser. No. 754,753, filed November 26, 1934. Forged interal with the barrel intermediate its ends is a radial flange II. In the zone of the flange II, the barrel has a plurality of radial cylinders l2 each of which has a cylinder port I3 opening into the barrel bore Illa. in position for cooperation successively with the ports 4 and 5 as the barrel rotates relative to the pintle.

The cylinders l2 are positioned in the zone of the flange II and open at their outer ends into radial guideways M which are formed in the flange II and have cylindrical front and rear walls for accommodating and guiding piston crossheads, later to be described. In order to constrain the barrel and pintle to fixed coaxial relation with positive radial capillary clearance between the wall of the bore Illa and the valve portion 301, the barrel is provided at one end of its bore with a counterbore portion forming an internal annular race l5 terminating at its inner end in a radial guide shoulder 16. At the opposite end, the barrel is counterbored to provide a bearing race I! and radial guide shoulder l8, the races l5 and I1 preferably being coaxial with respect to each other and aligned radially respectively with the races 3b and 3c of the pintle. Interposed between the aligned cooperating races of the pintle and barrel are sets of heavy duty cageless rollers l9 and 20, the rollers of each set being spaced a capillary distance from each other so that each roller of each set is freely rotatable about its own axis.

Referring to Fig. 14, one of the rollers I9 is illustrated, the rollers 20 being the same in form and function. The rollers I 9 preferably have square ends, as indicated at l9a, for cooperation respectively with the radial guide shoulders 3e and I 6. These rollers are provided for maintaining the pintle valve portion 3d in coaxial relation with respect to the barrel bore but with a positive radial clearance space between the barrel bore wall and pintle valve portion. Since the present structure is especially designed for high speed operation, it is desirable that the pitch diameter of the sets of bearings l9 and 20 be maintained as small as possible so that the circumferential travel of the rollers is reduced. For this reason, as will be more fully explained hereinafter, the present bearings are utilized. The bearings I9 have a diameter to length ratio from 1:2 to 1:3. Since they are spaced a capillary distance from each other and have the proper ratio, oil films form therebetween. Oil films likewise form between the ends of the rollers l9a and the shoulders 3e and I6, slight end clearance being provided for this purpose. Thus at high speed, the rollers are maintained by tenacious capillary films in proper parallelism with the axis of the pintle and are prevented from skewing in the races. The rollers 20 are correspondingly formed and retained in position at one end by the guide shoulder l8 and at the opposite end by a radial guide shoulder 220 formed on a portion of the impeller.

Secured to the barrel I0 is an impeller shaft 22 which is coaxial with the pintle and has a radial flange portion 22a and a coaxial boss 22b. The boss 22b is of proper diameter to be received snugly within the adjacent end of the counterbored race I! of the barrel, and can rotate slightly therein under sudden excessive torsional stresses. At its inner end, the boss has a smooth finished radial marginal wall which forms the outer guide shoulder 220 for the rollers 20 when the impeller is mounted in cooperative relation with the barrel.

As better illustrated in Fig. 3, the impeller flange portion 22a has a series of circumferentially spaced holes 22d, each of which extends parallel to the impeller axis. The barrel is provided at the end adjacent the impeller with internally threaded bores which are positioned in alignment respectively with holes 22d and receive suitable fastening bolts 23 for securing the impeller to the barrel. The impeller is drawn sufliciently tight to form a substantially sealed fit between the barrel and the impeller flange in juxtaposition with the end of the barrel, so that pressure fluid is retained at line pressure for effecting hydrostatic balance of the pintle.

In order to reduce shocks and vibrations and to provide a semi-flexible connection between the impeller and barrel, the holes 22d are of larger diameter than the bolts 23 and accommodate resilient washers or sleeves 24 which are preferably of rubber. Suitable lock washers 25 are interposed between the heads of the bolts 23 and the flange portion 220. for maintaining the bolts in firm seated position. Due to the resiliency of the sleeves 24, limited yieldably resisted circumferential movement of the impeller relative to the barrel is permitted under sudden or excessive shocks and stresses, which action damps shocks and torsional stresses which would otherwise be transmitted to and from the barrel and impeller.

The barrel is rotatably supported in the housing by heavy duty, sealed anti-friction ball bearings. As heretofore mentioned, the present pump is designed for high speed, high pressure operation, for which a comparatively viscous operating fluid is required. Such an operating fluid is not suitable for the large diameter rollers or anti-friction bearings when operatiing at high speed, and consequently the sealed bearings illustrated in Fig. 1 are provided so that a different lubricant can be used therein. At the end of the barrel l0 adjacent the shank portion of the pintle, the barrel has an annular shoulder 26 and radial shoulder 21. Mounted on the shoulder 26 is the inner race 28 of a set of ball bearings 29, the outer race 30 of which is fixedly secured in the radial flange wall lb of the housing l. Carried in the outer race 30 are fluid retaining shields 3| which form with the races a lubricant retaining trough in which the ball bearings 29 operate. Suitable bores, not shown, may be provided through the housing and outer race 30 for admitting lubricant to the balls 29. Thus the balls 29 may operate in a lighter, more desirable lubricant instead of the slip fluid from the pump or motor.

Another advantage of this type of bearing is especially pronounced in those cases in which the pump 'or motor is to operate in air which is laden with dust or grit, as in flour and grinding mills. In such cases, the shields 3| serve not only to retain lubricant, but also to protect all the internal portions of the pump from the infiltration of dust and grit. At the opposite end, the barrel has an annular external shoulder 3 and radial shoulder 34 corresponding to the shoulders 26 and 21 above described. The shoulder 33 accommodates the inner race 35 of a set of sealed ball bearings 36, corresponding to the ball bearings 29, the outer race of the ball bearings 36 being mounted in the end cover 2 in a manner corresponding to the race 30.

A suitable nut 31 is in screw threaded engagement with the .end of the barrel for adjusting and tightening the race 35 in the proper operating position. The races 28 and 35,.in addition to cooperating with the ball bearings 29 and 36, also form the means for locking certain reactance guide elements in position for constraining the rotary reactance in the proper axial position, with respect to the barrel, as will later be described.

Carried in the cylinders I2 respectively are radial pistons 40, each piston having a crosshead 4|, as better illustrated in Fig. 8. The crossheads 4|, in turn, have cylindrical fore andv aft or end faces 4Ia, in sliding cooperation with the cylindrical surfaces of the guideways l4, and flat lateral faces 41b which terminate substantially in the planes of the faces of the flange II, respectively.

Each of the crossheads 4| has a relatively large diameter pin receiving bore 4Ic extending parallel to the axis of rotation of the barrel. Mounted within the bores 4lc'are large diameter pins 42, each having reduced end portions 42a defining radial shoulders 421) with the larger diameter central portions of the .pins, as better illustrated in Fig. 10. The shoulders 42b and cylindrical operating surfaces of the pin ends 420 are merged by short radius fillets 42c, and the larger diameter portion of the pins are substantially coextensive with the crosshead bores axially of the bores. Each of the cross pins is mounted in its associated crosshead bore Me on capillary cageless needle rollers 43, the rollers being approximately coextensive axially of the pin with the crosshead bore and being constrained from axial displacement by suitable retaining washers 44. Thus the corresponding radial faces of the flange I l and faces 4") of the piston crossheads 4i, and the radial shoulders 42b of the cross pins lie in substantially common planes respectively, extending radially of the pump or motor.

For actuating the piston through the medium of the pins 42, a pair of -reactance rings 45 are provided, the rings being mounted for rotation about their common axis. As better illustrated in.Figs. 5 and 6, each of the rings 45 is preferably of rectangular cross section, having a depth radially of more than twice the width so as 'to provide as high a section modulus as possible for resisting hydraulic load and elastic and permanent deformation thereby. The rings 45 are mounted one at each side of the flange II. The inner radial faces of the rings, adjacent the faces of the flange, are smooth finished, hardened, and in juxtaposition with the flange faces,

slight operating clearance only being provided therebetween. Each ring 45 has an operating or reactance groove 46 coaxial with the ring and the races 48a.

' commodating the ends 42a of the cross pins. The

grooves 46 are preferably of slightly greater dimension radially than the diameter of the pin heads 42a so that the pins may roll therein at all times and not slide thereabout.

Due to the reduced frictional resistance to rotation between the large central, portion of each pin within its crosshead bore, the rolling frictional resistance is greater than that of the central portion so that, even with the reduced diameter, each pin will roll in the grooves 46 and not slide therein. In operating at high speed, it is necessary to prevent the pins from dragging and rotating the pistons about their own axes and thus causing the pins themselves to skew in the grooves 46. It is to prevent this action 46, are preferably bevelled; as indicated at' 46c,

but at a slightly greater radius from the fillets I 420 of the pins, so that the pins may roll freely relative to the rings 45 and yet be guided and prevented from skewing by cooperation of the shoulders'42b and the-marginal portions 46a of the rin s 45.

For rotatably supporting the rings 45, a reactance stator 48 is provided. The stator 48 has a pair of internal annular recesses 480, the bottom walls of which form races for accommodating heavy duty cageless rollers 49. The outer circumferential walls of the rings 45 are smooth finished and hardened and provide cooperative races for the rollers 49 through the medium of which rollers the rings are rotatably supported in coaxial relation to the stator. The rollers 49 are preferably smallerbut of the same general proportions as the rollers l9, as heretofore described, and are spaced a capillary distance from each otherso that they may rotate individually about their own axis while rolling about The rollers 49 are preferably coextensive axially with the associated rings 45 so as to provide as large a bearing surface as possible and are guided at their ends by the end walls of the races 48a. Since slip fluid from the pistons may enter the recesses 48a, the rollers 49 are always maintained with capillary oil films therebetween.

This structure, however, does not prevent axial separation or movement of the rings 45 but permits each of the rings to float freely axially and circumferentially.

Again it should be noted that no provision is made for connecting the barrel flange ll directly to the reactance rings 45 even though free rolling engagement between the piston cross pins and reactance rotor means is provided. By dispensing with any passages or holes in the flange H, greater strength is obtained and more material remains for providing a fly wheel effect. At the same time the barrel can be made of nitralloy or can be properly forged, polished or machined and nitrated without danger of deformation during subsequent heat treatment and resulting internal stresses from unequal distribution of the metal. In the absence of any such connecting means which generally areused to constrain the reactance rings to proper coaxial position, and further in the absence of a roller mounting for the reactance rings. which will constrain them to axial position, a separate means for this purpose must be provided. It is desirable also that the rings 45 be independently rotatable so that slight binding of one will not affect the other. It is likewise desirable that the rings be circumferentially floating relative to the barrel and independently of the rotation of thebarrel and of each other so that each cross pin does not continuously operate or oscillate along only a given short portion of the operating grooves 46. Instead, by providing for a gradual migration of the rings 45 circumferentially relative to the barrel, each cross pin, after a number of operations, will have oscillated gradually along the entire circumference of the rings. Thus concentration of wear is eliminated.

For constraining the rings to the proper position axially while permitting this gradual migration, the guide elements 50 are provided. The elements 50 comprise annular rings snugly received on the shoulders 26 and 33 respectively of the barrel, and have inner radial faces abutting the shoulders 21 and 34 of the barrel, respectively. The elements 50 also have outer radial faces which are in abutting relation to the inner ends of the races 28 and 35 respectively, so that when the races 28 and 35 are adjusted in proper position on the barrel ID, the elements 50 will be tightly clamped between the respective races and the corresponding shoulders 21 and 34. Each of the elements 50 is of suflicient radial dimension to provide a positive overlap of the inner radial face of the element with the outer radial face of the associated ring 45 at both maximum and minimum eccentricity of the rings 45. The elements 50, the flange II, the shoulders 42b of the cross pins, and rings 45 thus cooperate to constrain each other to proper axial positions while permitting the rings 45. to float axially with the barrel and circumferentially relative to the barrel. The moving operatingsurfaces of the rings 45 and elements 50, and also all other working surfaces of all elements, are smooth finished, polished and hardened.

Slight operating clearance is provided between the radial faces of the elements 50 and outer radial faces of the rings 45 so that capillary oil films may be formed therebetween. Since there is very little relative movement between the rings 45 and elements 50, the frictional resistance to rotation resulting from the elements 50 is negligible. At the same time the elements 50 define with the rings 45 and barrel flange annular circumferential fluid pockets for maintaining slip adjacent the outer end of the cylinders l2 to prevent the indrawing of air into the cylinders.

The reactance stator 48 is mounted for movement into different adjusted positions wherein its axis is coincident with or parallel to the axis of the pintle and in a plane defined by the axis of the pintle and dead center of the pintle bridges. Suitable control rods 52 are provided for adjusting the stator.

As heretofore described, the rings 45 are supported on relatively large rollers operating in recesses in the stator 48 and guided at their ends by the ends of the stator recesses. These rollers have a diameter length ratio of about 1:2 and are spaced a capillary distance apart from each other and are guided at their ends by the end walls of the recess so that they will not tend to skew in the recesses at high speed. Heavy rollers, such as l9 and 20, are provided between the pintle and barrel and are likewise spaced 9. capillary distance from each other and guided at their ends. The pitch diameter of the sets of rollers l9 and must be comparatively small, and at the same time, they must be capable of withstanding unbalanced hydrostatic load on the pintle in case the hydrostatic film balancing the pintle is prevented for any reason. If these rollers are made large in diameter, their speed of rotation is reduced as also it is reduced by small pitch diameter. The rollers on the pintle and between the stator and secondary rotor should operate as a set at the same number of revolutions per minute, but the pitch diameter of the rollers in the secondary rotor is about four times that of the pintle rollers and consequently they must revolve around the race at substantially four times the velocity of the pintle rollers to maintain the same angular velocity. Economy demands that the pintle rollers and rollers for the secondary rotor be so related that one group will not unduly outlast the other, as the structure would necessarily be rendered useless by the failure of either. The smaller bearings in the secondary rotor operate more efliciently at high speed than larger heavier rollers and at the same time they need not withstand so great hydraulic load as the pintle rollers but only the hydraulic piston load resultant. Thus the result is in keeping with the limitations of the rollers. The pintle rollers l9 and 20 must withstand about ten times as much load in case the pintle is at any instant in hydraulic unbalance. These rollers have a length diameter proportion from about 1:2 to 1:3 with about two to two and a half one thousandths of an inch clearance at their ends. Due to their relatively short length relative to their diameter, the end guiding is of extreme importance as otherwise they will skew and jam. Races and accessory equipment to prevent this cannot be used effectively, but by providing the guide shoulders 3e on the pintle and IS on the barrel, this installation of large, free full complement rollers is rendered possible. The same is true as to the rollers 20.

The use of the rollers of about the proportions illustrated for the .secondary rotor and at the pintle appears to provide rollers in both instances which will withstand about the same amount of wear, the larger rollers on the pintle being subjected to greater loads but traveling at less speed than the smaller rollers of the secondary rotor.

Having thus described my invention, I claim:

1. In a rotary, radial piston, pump or motor, a cylinder barrel having a plurality of radial cylinders, a flange on the barrel in the zone of the cylinders and having radial guideways aligned with the cylinders respectively, pistons in the cylinders respectively, valve means for the cylinders, heads on the pistons operative in said guideways, thrust means carried by the piston heads and extending beyond the heads parallel to the axis of rotation of the barrel, a reactance means for actuating the pistons comprising a pair of rings closely alongside the faces of the barrel flange respectively, said rings having reactance grooves aligned with each other and. opening toward the flange for receiving said thrust means for operatively connecting the pistons and reactance means, means rotatably supporting said rings in eccentric relation to the barrel, guide means carried by the barrel and having walls abutting the rings and constraining the rings from separation axially of the barrel while permitting free independent rotation thereof.

2. In a rotary, radial piston, pump or motor, a cylinder barrel having a plurality of radial cylinders, a flange on the barrel in the zone of the cylinders and having radial guideways aligned flange for receiving said pin ends for cooperating the pistons and reactance rotor, means rotatablyv supporting said rings, said rings having radial outer end faces respectively, guide means carried by, the barrel and positioned one at the outer radial face of each of said rings and each having an inner radial wall overlappingthe said outer wall of the associated ring and in full sliding engagement therewith for constraining the rings within fixed limits axially of the barrel while permitting rotation of the rings relative to the barrel.

3. In a rotary, radial piston, pump or motor, a cylinder barrel having a plurality of radial cylinders, a flange in the zone of the cylinders and having radial guideways respective to the cylinders, pistons in the cylinders respectively, valve means for the cylinders, crossheads on the pistons respectively and reciprocable along and guided by said guideways and substantially coextensive with the flange parallel to the axis of the barrel, a stator surrounding the barrel in eccentric relation thereto, a pair of axially spaced reactance rings rotatably mounted in the stator and disposed alongside the opposite faces of the flange, said rings having innerradial faces in juxtaposition with the ends of the flange respectively, and each ring having a circumferentially i continuous annular reactance groove, the groove of each ring opening toward the flange and being aligned with the reactance groove of the other ring, crosspins rotatably mounted in the crossheads and having reduced diameter end portions in rolling engagement with'said grooves,

radial shoulders on the pins adjacent the reduced end portions and in engagement with the rings constraining the pins to proper position relative to the rings,.anti-friction means mounting the rings-for free rotation relative to the barrel and movement axially relative thereto independently of each other, said rings having radially extending outer faces, guide elements carried by the barrel and having parallel radially extending inner faces in sliding engagement with the radially extending outer faces of the reactance rings in all relatively eccentric positions of the barrel and stator and constraining said rings within operating limits axially of the barrel.

4. In a rotary radial piston pump or motor, a cylinder barrel having a plurality of radial cylinders, a flange in the zone of the cylinders having radial guideways respective to the cylinders,

valve means for the. cylinders, pistons in thecylinders respectively, crossheads on thepistons reciprocable along and guided by said guideways and substantially coextensive with theflange parallel to the axis of the-barrel, a stator surrounding. the barrel in eccentric relation thereto, a pair of axially spaced rings, anti-frictionmeans rotatably mounting the rings in the stator for independent rotation and axial movement, said rings being disposed alongside the opposite faces of the flange respectively and having inner radial faces in juxtaposition with the flange, each ring having a continuous reactance groove opening toward the flange, the groove of each ring being aligned with the groove of the other ring,

crosspins rotatably mounted in the crossheads relatively eccentric positions of the barrel and stator and constraining said rings within operating limits axially of the barrel, and shoulders on the crosspins engaging the inner radial faces of the rings and being constrained by the rings to proper cooperative relation thereto.

5. In a rotary radial piston pump or motor, an inner rotor and an outer rotor eccentric thereto, one of said rotors comprising axially spaced reactance rings, means mounting the rings for independent rotatlon with respect to each other and for independent movement axially, the other rotor comprising a barrel with piston and cylinder assemblies carried thereby, means mounting the barrel for independent rotation about its axis, valve means for the assemblies, means in engagement with the rings and operatively connecting the assemblies thereto, and means in addition to the assemblies and carried by one of respect to each other while permitting free relative rotation thereof.

ELEK K. BENEDEK. 

